In many types of well applications, fluid samples are obtained and tested to help evaluate well fluid and/or geologic formation parameters. Some sampling operations may be performed during other well related operations, such as drilling operations. To obtain the desired fluid sample or samples, a sampling tool is deployed downhole into a wellbore and the fluid sample is drawn into the tool through a sampling port. A variety of pistons and/or other devices may be used in the sampling tool to intake the fluid sample into a sample chamber. However, problems can sometimes occur due to inadvertent closing and/or opening of the sample chamber with respect to the sampling port.